1. Field of the Invention
The present invention relates to a processing jig for holding an object processed with a processing apparatus.
2. Description of the Related Art
A thin film head and a magnetoresistive (MR) head are generally used as a magnetic head for a hard disk device. A thin film head is made up of a combination of a magnetic thin film and flat coils. An MR head uses a magnetoresistive element (MR element). An MR head is used for replay only and usually takes the form of a composite head integrated with a thin film head for recording.
A magnetic head for a hard disk device is made up of a magnetic head element formed at the trailing end of a slider floating slightly above the surface of a hard disk when rotating.
Magnetic heads such as a thin film head and an MR head described above are generally made through semiconductor manufacturing techniques. The manufacturing process of magnetic heads usually includes the steps of wafer formation, processing (machining) and assembly. In the wafer formation step a wafer as a substrate on which thin films are formed is made. Thin films such as magnetic poles, coils, insulating layers, protection layers are then formed on the wafer. In the processing step the wafer on which thin films are formed is cut into magnetic head materials. The magnetic head materials are ground and polished to form sliders each including a magnetic head element. The sliders are each mounted on a suspension in the assembly step.
An example of the processing step will now be described. In the processing step a wafer on which thin films are formed is cut in one direction to form bar-like magnetic head materials. Each bar-like magnetic head material is fixed to a jig to be processed through lapping and so on. The bar-like magnetic head material includes a plurality of magnetic head elements arranged in a line. The bar-like magnetic head material is divided into individual sliders, having been processed through lapping, polishing and so on. In such a processing step it is required that a throat height and an MR element height of every magnetic head element included in the bar-like magnetic head material fall within a certain limited tolerance. It is required as well that the profile irregularity of the surface processed falls within a specific permissible range.
An apparatus for performing such a processing step is disclosed in U.S. Pat. No. 5,620,356. A jig for processing magnetic heads is disclosed in U.S. Pat. No. 5,607,340. A lapping control apparatus in disclosed in Japanese Patent Laid-open No. 2-95572 (1990) for controlling a throat height through observing a resistance of an MR element.
As shown in U.S. Pat. Nos. 5,620,356 and 5,607,340 mentioned above, a jig of related art is fixed to a processing apparatus at two points in a horizontal direction. However, there may be a difference in level between the two points in the processing apparatus to which the jig is fixed. Furthermore the two points may not be adequately parallel to each other. No matter how minute, such a difference in level and bad parallelism are significantly large compared to the profile irregularity tolerable for the surface processed of the magnetic head material. Accordingly, such a jig of related art has a problem that a difference in level and bad parallelism between the two points in the processing apparatus to which the jig is fixed affect the profile regularity, flatness in particular, of the surface processed of the magnetic head material. Consequently yields of magnetic heads are reduced while inspection steps for magnetic heads are required to be increased.